Jackson County prosecutors say Harrell Johnson, 29, was high on drugs when he knocked young Erica Green to the floor after she refused to go to bed. Johnson, along with the girls' mother, did not seek medical help as the girl lay dying for nearly 10 hours.

Prosecutors claim the couple eventually took the girl's body out of the house and that Johnson decapitated her and dumped the body in the woods. Johnson is charged with first-degree murder.

Opening statements start Monday, with prosecutors planning to focus on Johnson's refusal to seek medical help for the girl before her death.

The girl's headless body was discovered in a wooded Kansas City park area in 2001, and a volunteer searcher found her head several days later. For four years, the case haunted residents, who longed to know who the girl was and who could have killed her in such horrific fashion.

Erica was identified in 2005 through a tip given to a community activist, who was among those who kept attention on the case.

"I'm glad we're at the final steps of justice and getting Erica Green justice," said Alonzo Washington, the activist who helped break the case with a tip he received from what turned out to be a family member of the girl.

Defense lawyers are expected to argue that there's no proof Johnson deliberately caused the girl's death.

"We certainly intend to do everything we can to challenge the state's case and afford Mr. Johnson his right to the trial that he would like to have," defense attorney Chris Slusher said.

Prosecutors plan to call Michelle Johnson, Erica's mother and Harrell Johnson's wife, as a witness. The two were married a year after Erica's death, but she pleaded guilty to second-degree murder last year and agreed to testify against her husband.

The trial is expected to last about a week. If convicted of first-degree murder, the only possible sentence for Harrell Johnson would be life in prison without parole. Prosecutors are not seeking the death penalty, partly because Johnson agreed to withdraw his request to have the case moved out of Kansas City.